1. Field of the Invention
The present invention relates to a mobile terminal apparatus, a power control method for the apparatus, and a storage medium storing a program for the method, and more specifically to a mobile terminal apparatus, and a power control method for the apparatus, and a storage medium storing a program for the method which have a display unit and a pen-input unit capable of inputting handwriting, and can input a character without assigning an input space to a liquid crystal display unit and reduce power consumption by the pen-input unit.
2. Description of the Prior Art
Since a mobile terminal apparatus such as a mobile phone, etc. is requested to be smaller and lighter, the keys for inputting characters, etc. cannot be provided on the surface of its body, etc., and therefore the ten-key for use in inputting a phone number is used also in inputting hirakana (the cursive from of kana) and alphabetic characters. Therefore, when character input is performed, it is necessary to repeatedly operate the ten-key on one character, thereby causing trouble of performing character input. Inputting a phone number is no serious trouble because character input is performed at operation starting, adding some phone numbers, or changing some phone numbers, etc. However, in sending mail which has popularly been performed these days, the trouble is serious. Accordingly, suggested is a mobile terminal apparatus having a display unit with an input panel capable of inputting a handwritten character, a reply character, and other items by providing a touch sensor for the liquid crystal display unit (LCD), and pressing a specified portion by a finger or an input pen.
FIG. 9 shows the conventional mobile terminal apparatus provided with an input panel. In this example, a foldable mobile phone is used as a mobile terminal apparatus. A mobile phone 30 is formed as a foldable unit by an upper housing portion 31 and a lower housing portion 32 coupled by a hinge unit 33. The upper housing portion 31 contains a display unit 34 with an input panel having a liquid crystal display unit. The lower housing portion 32 is provided with a ten-key 35 and a menu key 36. The display unit 34 with an input panel has a screen on which an input panel of a transparent film is applied, and functions as a display device and input device.
In FIG. 9, by pressing using a pen an image of an icon, software, a keyboard, etc. displayed on the screen of the display unit 34, corresponding characters and numerics can be input as data in character input processing. Thus, with the configuration of providing the display unit 34 with an input panel, a mixture of hirakana, katakana (square form of kana), alphabetic characters, numerics, etc. can be input, kanji (Chinese character) can be directly input, and the inputting operation is easily performed when handwritten characters are input.
However, with the configuration shown in FIG. 9, it is necessary to reserve a pen-input area on a part of the screen of the display unit 34 when a handwritten character is input, and there is the problem that the remaining display area is reduced. To solve the problem, for example, Japanese Patent Application Laid-open No. Heisei 11-341114 has been developed as a straight type mobile phone provided with a flip containing a tablet inside the flip as an inputting operation unit, thereby allowing the liquid crystal display means to be used only for display.
With the configuration including an input panel as shown in FIG. 9 or an additional tablet of Japanese Patent Application Laid-open No. Heisei 11-341114, power is supplied to the input panel and the tablet although they are not in use. Therefore, the power consumption is not to be ignored, and the continuous service hour is shortened. To solve the above mentioned problems, for example, Japanese Patent Application Laid-open No. Heisei 2-178817 has been developed to apply pressure to a touch panel using a finger, etc., supply power to the touch panel when an inputting operation is detected, and prevent supply of power to the touch panel when no inputting operation is detected (not in use), thereby reducing the power consumption of the touch panel.
However, according to the conventional mobile terminal apparatus, for example, the mobile phone of Japanese Patent Application Laid-open No. Heisei 11-341114 uses a tablet which excels in the operability as a function key, but cannot input a handwritten character. The mobile terminal apparatus of Japanese Patent Application Laid-open No. Heisei 2-178817 detects an unintentional touch of a touch panel by an operator as a touch status although the operator has no intention of using the touch panel, thereby powering the touch panel unwillingly. Thus, there have been a number of problems in reducing the power consumption, and no perfect means for reducing power consumption have been developed.